Manufacture of pinacol



Patented F eb. 26, 1929 V UNITED STA S PATENT o HENRY BERLIN, on NEW YORK, N. in, 59161103 170 m'rnaiu'rioiun PATENTS,

nnvnnorunnr comm, or wrmmm'ron, DELAWARE, AI coarom'rron I or DELAWARE.

. No Drawing.

My invention relates to the production of tetramethylglycol OH3CoH"-CHl CHI- 034311;

and its objects are to provide novel and practically useable methods (1) of preparing pinacol hydrate by reacting acetone .or its honiologues with certain other substances or their equivalents, ashereinafter set forth; (2) of preparing anhydrous pinacol directly without first producing the hydrate.

I am aware of United States Patent N 0. 1,068,777 granted to August' Jonas and Eduard Tschunkur, assignors to Farbenfabriken vorm. Friedr. Bayer & (30., July 29, 1913, and United States Patent No.

1,079,916 granted to the same parties on November 25, 1913 but after careful .ex-

periment with the processes disclosed or purporting to be disc osed, in these patents,

' sult.

I have found that said processes are unworkable and that the agents and manipulations specified in said patents, when employed inthe manner directedilwill not give the results claimed or any 'o't er useful re- Long experimentation with the reactions here concerned has convinced me that in order to successfully produce pinacolfrom acetone or its homolo es it is necessary to use agents and manipulations thereof substantiall 4 The invention 1s based upon this discovery.

(1) The following is a specific example of the method whichI have devised for producing pinacol hydrate.

1600 grams of acetone ((3H,),CO is placed in a .vessel having a re ux condenser, with SOgr'ams of aluminumand from 70 to 100 grams of car- The amount of the carbon tetrachlorid introduced initially is important. If substan.- tially less than 7 0 grams is used the reaction ordinarily does not take place and if inexceptional cases. it does take place it is .'very slow ,in starting and furnishes insignificant yields, even from the laboratory point of view. If the amount ismuchan excess of 100 grams, say by 10 or 15' .grams',

the reaction is too violent. After the mixtiga has boiled for two .or three minutes,

as hereinafter described.

iprovided with an agitator and is addedat onetime grams of cry mamrrnc'runn on rmAcoL.

- Application filed December :26, 192a. serial no. 156 089.

talline mercuric. chloride-HgCl,-and the boiling is continued for, ten to fifteenmin-' utes. The heat is then removed andthe reaction continues exothermically. When mostof the C01 has been consumed and thereaction slows down 10grams of CCl isv added which livens up the reaction. The 7 tiesinsteadof intermittently in the quantities noted. Heat is then applied to insure complete reaction and the substance 1 is cooled or allowed to cool to from 40 to 50 Centigrade, and 330 grams of water is run into the batch and the material jagitated, then boiled for from one-half'to one hour andthereafter cooled and filtered. Preferably the filter cake is washed with acetone to increase the yield. The filtrate and liquid,

from the washing of the filter cake are combined and evaporated in-the presence of 'sodium carbonate, 2 to 3 grams of sodium carbonate being preferably employed,"-the evaporation being at atmospheric pressure and continued until the temperature of the heat ed substances is about 80 centigrade and the temperature of the. vapors distllling over is from" to .72 Centigrade. 150 grams of 'ice water is then added to the" res'ldne'and The carbon, tetr'achlorid, added" The total on cooling to 15 centigrade'pinacol' hydrate washed wan carbon tetrachlorid to remove impurities. The crystals will be snow-white and very pure, the yield being, according to my experience, about 65% of the theoretical, based on the aluminum used. The excess ,of carbon tetrachlorid and acetone driven off by distillation can be saved and re-used. a

While my experiments have been confined to the use of acetone, it"should be possible, on'theoretical grounds, to useany of the homologues of acetone. cnric chloride any sdluble mercury salt soluble in acetone (or its homologue if used) end-decomposable byalumimun can be used.

place of mer- 1 is not as satisfactory.

- The acetoneingredie'nt can be used in larger ings, or in sheets.

or smaller proportions than indicatedbutthis will, in the first case, give an unnecessary excess without any beneficial result and in the second case will furnish a product of undesirable consistency and appearance. The aluminum may begranulated, in shav- I have found that the use of powdered aluminum, contrary to the statement of the patents abovereferred to,

To produce anhydrous pinacol from pinacol hydrate, prepared as above or otherwise,

100 grams 0 plnacol hydrate is melted, for example, on a water bath, andis mixed with 100 grams of a 50% caustic soda solution I and the mixture while warm agitated for .through the adding ofthe carbon tetra- 1 equivalent of the ten to fifteen minutes and then allowed to settle. The material separates into two layers, the upper layer consisting of anhy drous pinacol with possibly some impurities. This layer'may be taken off and distilled to remove the impurities. -On cooling .the distillate will crystallize as pure,-snow-'whiteprismatic crystals. In place of caustic soda one ma use potassium hydroxide, or any other a aline dehydrating agent which does not dissolve pinacol or react'with pinacol.

(2) To produce anhydrous pinacol directly, without,,that is, first producing the hydrate, the process as above outlined for the production of the hydrate is followed chlorid in 10 gram increments. The material is then cooled and a solutionof causticsoda is added in an amount twice the aluminum used. The mixture when allowed to stand after preliminary stirring will separate into layers, the upper one of hich consists of an acetone solution of pinacbl. This is syphoned off and fractionally distilled in vacuo.'-

' trained worker." In such respects,

The above description is based upon batches of relatively small size. It will be understood that when larger quantities of material are handled certain details of the operations, such as the duration of the heating and the like, may have to be varied. These and other modifications will be entirely .withiri the ordinary skill of the therefore, the method may be modified considerably without departure from the principles of the invention and all such. modifications, within the scopeof the appended claims, are

to be considered as within thecontemplation of my invention.

In carrying out process -(2), potassium or any other alkaline dehydrathydroxide, ing agent which does not react or'mix with pinacol may be employed instead of caustic soda. The proportions of the ingredients ma also be varied, tosome extent, without defeating the aims in view, but the propor tions given above are deemed best.

I claim: p

1. Method of producing pinacol by reacting together acetone, or its homologues,

aluminum and a mercury salt soluble in theketone and decomposable by aluminum,

" which comprises using carbon tetrachlorid as a reaction producing agent, and introducing the same into. the mixture of the other ingredients intermittently, one portion initially. and the other portions as. the reaction slows down so as to preventviolence of re action, and thereafterdecomposing the reaction product and separating out the'solution of pinacol.

2. Method of claim 1 in which the ingre dients are in substantially the following pro;

.portions by weight: acetone 160 parts;

aluminum 8 parts; mercuricchloride 3 parts; and carbon tetrachlorid, introduced initially, 7 to '10 parts, with subsequent addi-" tions' of the carbon tetrachlorid of 1 part each, as the reaction slows down, to a tota of about 17 arts.

3. Method of claim 1 in which the ingredients are in substantially the following proportions by weight: 'acetone 160 parts;

aluminum 8 parts; mercuric chloride 3% parts; and carbon tetrachlorid, introduced initially, 7 to 10 parts with subsequent additions of the carbon tetrachlorid of one part each, to a total of about 17 parts; and in which the vreaction productof acetone, aluminum, mercuric chloride and carbon tetrachlorid is cooled, 330 parts of water added, the mixture boiled, cooled, filtered, evaporated'in the presence of sodium carbonate,

to remove chiefly acetone and excess of carbon tetrachlorid,-and the residue mixed with 150 parts of water and crystallized.

4. Method of claim 1 in which the ingredients are in substantially the following proaluminum 8' parts; mercuric chloride 3 parts; and'carbon tetrach1orid, introduced,

initially, 7 to 10 parts with subsequent additions'of the carbon tetrachlorid of one part each, to a total of about 17 parts, and in which the reaction product of acetone, aluminum, mercuric chloride and carbon tetrachlorid is cooled, 330 parts of water added, the mixture boiled, cooled, filtered, the filter cake washed with acetone and the filtrate and washings of the filter cake evaporated portions by weight: acetone 160 parts;

in the resence of sodium carbonate to re-,

move 0 iefly acetone and excess of carbon tetrachlorid, parts of Water and crystallized.

HENRY BERLIN.

and the residue mixed with 

